1. Field of the Invention
The present invention relates to a substrate processing apparatus for applying processing to substrates.
2. Description of the Background Art
A substrate processing apparatus is used to apply a variety of processing to substrates such as semiconductor substrates, substrates for use in liquid crystal displays, plasma displays, optical disks, magnetic disks, magneto-optical disks, photomasks, and other substrates.
Such a substrate processing apparatus typically applies a plurality of successive processing to a single substrate. The substrate processing apparatus as described in JP 2003-324139 A includes an indexer block, an anti-reflection film processing block, a resist film processing block, a development processing block, and an interface block. An exposure device is arranged adjacent to the interface block as an external device separate from the substrate processing apparatus.
In the above-described substrate processing apparatus, a substrate is carried from the indexer block into the anti-reflection film processing block and the resist film processing block, where the formation of an anti-reflection film and resist film coating processing are applied to the substrate. The substrate is then transported to the exposure device through the interface block. After exposure processing has been applied to the resist film on the substrate by the exposure device, the substrate is transported to the development processing block through the interface block. In the development processing block, development processing is applied to the resist film on the substrate to form a resist pattern thereon, and the substrate is subsequently carried into the indexer block.
With recent improvements in the density and integration of devices, making finer resist patterns have become very important. Conventional exposure devices typically perform exposure processing by providing reduction projection of a reticle pattern on a substrate through a projection lens. With such conventional exposure devices, however, the line width of an exposure pattern is determined by the wavelength of the light source of an exposure device, thus making it impossible to make a resist pattern finer than that.
For this reason, a liquid immersion method is suggested as a projection exposure method allowing for finer exposure patterns (refer to, e.g., WO99/49504 pamphlet). In the projection exposure device according to the WO99/49504 pamphlet, a liquid is filled between a projection optical system and a substrate, resulting in a shorter wavelength of exposure light on a main surface of the substrate. This allows for a finer exposure pattern.
In the projection exposure device according to the aforementioned WO99/49504 pamphlet, exposure processing is performed with the substrate and the liquid being in contact with each other. Accordingly, if the contaminants adhere to the substrate before the exposure processing contaminants are mixed in the liquid.
Although a variety of film formation processing are applied to the substrate before the exposure processing, an edge of the substrate may be contaminated in the process of these film formation processing. If the exposure processing is applied to the substrate with the edge of the substrate contaminated, a lens of the exposure device is contaminated, possibly generating a defective dimension and a defective shape of the exposure pattern.
Also, in the above conventional substrate processing apparatus, the component included in an anti-reflection film, a resist film or the like at or around the edge of the substrate may be eluted or be extracted in an immersion liquid in the exposure processing by the liquid immersion method. Consequently, the lens of the exposure device may be contaminated, possibly generating a defective dimension and a defective shape of the exposure pattern.